Merge branch 'trusty'

Signed-off-by: caleb miles <cmiles@pivotallabs.com>
Silence apt-get upgrade

apt-get upgrade used to pop up question which caused packer to hang

Signed-off-by: Andrea Law <alaw@pivotallabs.com>
Rename virtualbox to virtualbox-iso

Packer 0.5.0 is using virtualbox-iso now

Signed-off-by: Andrea Law <alaw@pivotallabs.com>
Merge remote-tracking branch 'upstream/master' into bskyb/trusty

Conflicts:
	bosh-stemcell/template.json